17-Cal Bore Guides — The Challenge
The problem is, it’s hard to find a well-designed, quality bore guide for 17-caliber rimfire rifles. With many 17 HMR (and 17 Mach 2) rifles, you encounter mechanical interference when you try to use a standard bore guide to protect the delicate chamber edge and the bottle neck area of the chamber. A fixed ejector is in the way. On many 17 HMR rifles, this little “shark fin” ejector is right in line with the chamber and is fixed — it doesn’t retract. Therefore the kind of bore guide you might use for centerfire rifles won’t work in 17 HMRs — it will hang up on the ejector.

Polymer bore guides exist for this type of action, but they are typically open-bottom designs that do not enter and seal the chamber. These open-bottom designs don’t protect the delicate chamber edge or the bottleneck area of the chamber, and they also allow some seepage of solvents out of the chamber. That’s why Roy Bertalotto created his RVB Precision Bore Guide for 17 HMR rifles. The 7075 aluminum tube on his Bore Guide is thin enough to pass by the ejector, yet it is extremely rigid. (Photos below.)

Roy explains: “My bore guide is made of 7075 anodized aluminum tubing, which is totally unaffected by any type of cleaning solution. One end is swagged down to fit completely into the chamber of a 17 HMR rifle. This guides your cleaning rod perfectly to the bore without touching the chamber walls or front edge of the chamber. The tight fit of the bore guide in the chamber also stops cleaning solvents from getting into the action, magazine, and trigger housing.” (Editor: Solvent seepage can do damage. We had a 17 Mach 2 rifle that rusted internally because solvents leaked past an open-bottom bore guide.)

Using the RVB 17 HMR Guide – Once the bore guide is in place, slide the supplied aluminum bushing over the tube, and gently push the bushing into the rear of the action. This centers the guide rod in the action to keep the guide rod tube aligned. Once the guide rod and bushing are in place, you can use a 17-caliber cleaning rod* with patches and/or brushes to clean the barrel. Use the rod normally, but make sure your patches are quite small and don’t apply too much pressure as these small-diameter rods can kink if you try to force over-size patches down the bore.

Roy tells us: “Yes, I make the bore guides out of 1616 aluminum arrow shafts. The only material on earth that fits EXACTLY what is needed. I buy the shaft material as simple tubing from Easton. It is hard anodized, the perfect wall thickness and doesn’t look too bad either.”

* NOTE: You really do need a dedicated .17-cal cleaning rod for this job. Most other rods are too fat to pass through the barrel. Dewey Mfg. makes a decent 17-caliber cleaning rod that is reasonably stiff and doesn’t kink too readily. It is available in 7″, 11″, 18″, 26″, and 36″ lengths, either bare stainless steel or with a nylon coating. For use with the Bertalotto Bore Guide, we prefer the nylon-coated version, in either 26″ or 36″ lengths, depending on barrel length.

If you have a high comb on your rifle, you may need extra length to avoid interference with the rod handle. Use this formula to determine correct rod length: Length of barrel + action or breech rod guide length + 2-3″ clearance + high comb if applicable = total rod length needed.

There are other quality 17-cal cleaning rods, but we’ve used the Dewey and it functioned well. The nylon coating cleaned easily and was gentle on the throat and crown. You should clean the coating before and after each use to ensure it does not embed grit or other contaminants.